Dutch firm Houthoff is thought to have advised Petro Rio, but this could not be confirmed prior to publication.

The transaction was signed on 26 October, but no deal value was disclosed.

Chevron controls production in Frade. It owns a 51.74% in the field, while Petrobras owns 30%. Petro Rio now owns the remaining 18.26% stake. The field is located 120 kilometres off Rio de Janeiro’s coast, in the Campos basin.

Several firms represented Chevron in a long litigation following an oil spill at Frade in 2011. Since then, the company has made efforts to recover the level of production in the field, but Petrobras’ decision not to drill new wells in the area recently derailed plans, according to Reuters.

Petro Rio’s chief executive said the company is willing to acquire Petrobras’ stake in Frade. The state-owned company has been following a vigorous divestment programme since it was hit by a sprawling corruption scandal, probed by Operation Car Wash. It also has a high debt burden as a result of investment commitments in Brazil’s pre-salt exploration areas.

In December the company undertook its largest-ever upstream sale, handing a 25% stake in its third-largest oil field in Brazil to Norway’s Equinor (formerly known as Statoil) for US$2.9 billion. In the same month, Petrobras’s retail and distribution arm carried out a US$1.6 billion IPO to help tackle the company’s debt load. Petrobras has also refrained from further investment in Brazil’s pre-salt, paving the way for international companies to obtain larger stakes in Brazil’s oil exploration sector.